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Abstrak :
ABSTRAK Penelitian ini membahas tentang proses pembuatan dan karakterisasi kertas karbon komposit berbasis bahan karbon dari serabut kelapa untuk aplikasi Gas Diffusion Layer (GDL) PEMFC. Kertas karbon komposit harus berpori, bersifat konduktif, dan hidrofobik agar dapat berfungsi sebagai GDL. Proses pembuatan kertas karbon komposit terdiri dari 3 tahap. Pada tahap pertama, bahan karbon berbentuk serat dengan panjang ± 1 mm dan serbuk karbon 200 mesh dihasilkan dari proses karbonisasi dan pirolisis serabut kelapa hingga suhu 1300°C. Pembuatan kertas karbon komposit pada tahap kedua dilakukan dengan cara mencampurkan serat dan serbuk karbon yang dihasilkan pada tahap pertama dengan polimer ethylene vinyl acetate (EVA) dan poly ethylene glycol (PEG) sebagai binder ke dalam pelarut xylene. Komposisi penggunaan antara serat dan serbuk karbon divariasi dari 0 wt% hingga 80 wt%. Proses pencampuran dilakukan pada suhu 90°C hingga membentuk slurry, dan dilanjutkan dengan proses pencetakan dengan teknik hand lay-up casting dan calendering. Berdasarkan hasil pengujian konduktivitas listrik, kertas karbon komposit dengan 70 wt% serat karbon dan 10 wt% serbuk karbon memiliki nilai konduktivitas tertinggi yaitu sebesar 2,22 S/cm. Kombinasi penggunaan serat karbon dengan aspek rasio yang lebih tinggi dan serbuk karbon menghasilkan efek sinergi yang dapat meningkatkan konduktivitas listrik kertas karbon komposit. Proses dilanjutkan dengan pelapisan bahan hidrofobik polytetrafluoroethylene (PTFE) pada tahap ketiga dengan cara merendam kertas karbon dalam suspensi PTFE selama 30 menit kemudian dipanaskan hingga suhu 350°C. Konsentrasi suspensi PTFE divariasi dari 0 wt%, 10 wt%, 20 wt%, dan 30 wt% untuk menghasilkan kertas karbon dengan sifat yang optimum. Berdasarkan hasil karakterisasi dan analisis kertas karbon dengan 10 wt% PTFE memiliki konduktivitas listrik tertinggi sebesar 2,09 S/cm, porositas tertinggi sebesar 73,63%, densitas sebesar 0,42 gram/cm3, bersifat hidrofobik dengan sudut kontak sebesar 128,9o, namun sifat mekaniknya masih rendah dengan kekuatan tarik sebesar 0,02 kN/m dan Modulus Young sebesar 4,57 kN/m.

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ABSTRACT This study discusses the process of manufacture and characterization of carbon composite paper based on carbon material of coconut fibers for Gas Diffusion Layer (GDL) of PEMFC. Carbon composite paper should be porous, conductive, and hydrophobic in order to serve as GDL. The manufacturing process of carbon composite paper consists of three stages. In the first stage, carbon fiber with a length of ± 1 mm and carbon powder of 200 mesh produced from pyrolysis and carbonization process of coconut fibers at 1300°C. Manufacture of carbon composite paper at the second stage conducted by mixing the carbon fibers and carbon powder produced in the first stage with ethylene vinyl acetate (EVA) and poly ethylene glycol (PEG) as binder in the xylene as solvent. The composition of carbon fibers and carbon powder was varied from 0 wt% to 80 wt%. The mixing process is carried out at 90°C to form a slurry, followed by the hand lay-up casting and calendaring to form a sheet of paper. Based on the results of electrical conductivity test, carbon paper composite with 70 wt% carbon fiber and 10 wt% carbon powder has the highest conductivity of 2,22 S / cm. Combination of carbon fiber with a higher aspect ratio and carbon powder generates synergy effects which increase the electrical conductivity of carbon composite paper. The process is continued with a hydrophobic treatment in the third stage by immersing carbon paper in a suspension of polytetrafluoroethylene (PTFE) for 30 minutes and then heated to a temperature of 350°C. PTFE suspension concentration was varied from 0 wt%, 10 wt%, 20 wt% and 30 wt% to produce the carbon paper with optimum properties. Based on the results of characterization and analysis, carbon paper with 10 wt% PTFE has the highest electrical conductivity of 2,09 S/cm, the highest porosity of 73,63%, density of 0,42 g/cm3, contact angle of 128,9o, but the mechanical properties are still low with the tensile strength of 0,02 kN/m and Young's modulus of 4,57 kN/m

Abstrak :
The gas diffusion layer (GDL) is one of the critical components of a proton exchange membrane fuel cell (PEMFC). It is generally made of a fossil-fuel-based carbon material. In this study, carbon composite paper (CCP) for GDL was prepared by using carbon material obtained from coconut coir. To obtain the CCP, 80 wt% carbon material from the coconut coir and 20 wt% polymer binder (ethylene vinyl acetate and polyethylene glycol) were mixed in xylene solvent at 100°C, cast on molded glass, and then rolled. The carbon material consists of a mixture of carbon fibers (length: 2 mm) and powders (size: 74 µm). Subsequently, the CCP was treated with polytetrafluoroethylene solution (10 wt%). The physical properties of the CCPs, such as through-plane electrical conductivity, porosity, density, and hydrophobic properties, were investigated. Scanning electron microscopy and energy-dispersive spectroscopy mapping were used to analyze the morphology and polytetrafluoroethylene (PTFE) distribution in the CCP. The through-plane conductivity test showed that CCP with 70 wt% carbon fiber, 10 wt% carbon powder, and 20 wt% polymer was the optimum sample, and it showed the highest electrical conductivity of 2.22 S cm-1. The physical properties of PTFE-treated CCP, such as porosity, density, and contact angle, were almost similar to that of commercial carbon paper used as a GDL. Therefore, the CCP prepared from coconut coir can be applied as a GDL in a PEMFC.

Abstrak :
The gas diffusion layer (GDL) is one of the critical components of a proton exchange membrane fuel cell (PEMFC). It is generally made of a fossil-fuel-based carbon material. In this study, carbon composite paper (CCP) for GDL was prepared by using carbon material obtained from coconut coir. To obtain the CCP, 80 wt% carbon material from the coconut coir and 20 wt% polymer binder (ethylene vinyl acetate and polyethylene glycol) were mixed in xylene solvent at 100°C, cast on molded glass, and then rolled. The carbon material consists of a mixture of carbon fibers (length: 2 mm) and powders (size: 74 µm). Subsequently, the CCP was treated with polytetrafluoroethylene solution (10 wt%). The physical properties of the CCPs, such as through-plane electrical conductivity, porosity, density, and hydrophobic properties, were investigated. Scanning electron microscopy and energy-dispersive spectroscopy mapping were used to analyze the morphology and polytetrafluoroethylene (PTFE) distribution in the CCP. The through-plane conductivity test showed that CCP with 70 wt% carbon fiber, 10 wt% carbon powder, and 20 wt% polymer was the optimum sample, and it showed the highest electrical conductivity of 2.22 S cm-1. The physical properties of PTFE-treated CCP, such as porosity, density, and contact angle, were almost similar to that of commercial carbon paper used as a GDL. Therefore, the CCP prepared from coconut coir can be applied as a GDL in a PEMFC.